Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 2276 insertions, 0 deletions

diff --git a/net/9p/client.c b/net/9p/client.c
new file mode 100644
index 000000000..84b93b04d
--- /dev/null
+++ b/net/9p/client.c
@@ -0,0 +1,2276 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 9P Client
+ *
+ *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
+ *  Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net>
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/idr.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/sched/signal.h>
+#include <linux/uaccess.h>
+#include <linux/uio.h>
+#include <net/9p/9p.h>
+#include <linux/parser.h>
+#include <linux/seq_file.h>
+#include <net/9p/client.h>
+#include <net/9p/transport.h>
+#include "protocol.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/9p.h>
+
+#define DEFAULT_MSIZE (128 * 1024)
+
+/* Client Option Parsing (code inspired by NFS code)
+ *  - a little lazy - parse all client options
+ */
+
+enum {
+	Opt_msize,
+	Opt_trans,
+	Opt_legacy,
+	Opt_version,
+	Opt_err,
+};
+
+static const match_table_t tokens = {
+	{Opt_msize, "msize=%u"},
+	{Opt_legacy, "noextend"},
+	{Opt_trans, "trans=%s"},
+	{Opt_version, "version=%s"},
+	{Opt_err, NULL},
+};
+
+inline int p9_is_proto_dotl(struct p9_client *clnt)
+{
+	return clnt->proto_version == p9_proto_2000L;
+}
+EXPORT_SYMBOL(p9_is_proto_dotl);
+
+inline int p9_is_proto_dotu(struct p9_client *clnt)
+{
+	return clnt->proto_version == p9_proto_2000u;
+}
+EXPORT_SYMBOL(p9_is_proto_dotu);
+
+int p9_show_client_options(struct seq_file *m, struct p9_client *clnt)
+{
+	if (clnt->msize != DEFAULT_MSIZE)
+		seq_printf(m, ",msize=%u", clnt->msize);
+	seq_printf(m, ",trans=%s", clnt->trans_mod->name);
+
+	switch (clnt->proto_version) {
+	case p9_proto_legacy:
+		seq_puts(m, ",noextend");
+		break;
+	case p9_proto_2000u:
+		seq_puts(m, ",version=9p2000.u");
+		break;
+	case p9_proto_2000L:
+		/* Default */
+		break;
+	}
+
+	if (clnt->trans_mod->show_options)
+		return clnt->trans_mod->show_options(m, clnt);
+	return 0;
+}
+EXPORT_SYMBOL(p9_show_client_options);
+
+/* Some error codes are taken directly from the server replies,
+ * make sure they are valid.
+ */
+static int safe_errno(int err)
+{
+	if (err > 0 || err < -MAX_ERRNO) {
+		p9_debug(P9_DEBUG_ERROR, "Invalid error code %d\n", err);
+		return -EPROTO;
+	}
+	return err;
+}
+
+/* Interpret mount option for protocol version */
+static int get_protocol_version(char *s)
+{
+	int version = -EINVAL;
+
+	if (!strcmp(s, "9p2000")) {
+		version = p9_proto_legacy;
+		p9_debug(P9_DEBUG_9P, "Protocol version: Legacy\n");
+	} else if (!strcmp(s, "9p2000.u")) {
+		version = p9_proto_2000u;
+		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.u\n");
+	} else if (!strcmp(s, "9p2000.L")) {
+		version = p9_proto_2000L;
+		p9_debug(P9_DEBUG_9P, "Protocol version: 9P2000.L\n");
+	} else {
+		pr_info("Unknown protocol version %s\n", s);
+	}
+
+	return version;
+}
+
+/**
+ * parse_opts - parse mount options into client structure
+ * @opts: options string passed from mount
+ * @clnt: existing v9fs client information
+ *
+ * Return 0 upon success, -ERRNO upon failure
+ */
+
+static int parse_opts(char *opts, struct p9_client *clnt)
+{
+	char *options, *tmp_options;
+	char *p;
+	substring_t args[MAX_OPT_ARGS];
+	int option;
+	char *s;
+	int ret = 0;
+
+	clnt->proto_version = p9_proto_2000L;
+	clnt->msize = DEFAULT_MSIZE;
+
+	if (!opts)
+		return 0;
+
+	tmp_options = kstrdup(opts, GFP_KERNEL);
+	if (!tmp_options)
+		return -ENOMEM;
+	options = tmp_options;
+
+	while ((p = strsep(&options, ",")) != NULL) {
+		int token, r;
+
+		if (!*p)
+			continue;
+		token = match_token(p, tokens, args);
+		switch (token) {
+		case Opt_msize:
+			r = match_int(&args[0], &option);
+			if (r < 0) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "integer field, but no integer?\n");
+				ret = r;
+				continue;
+			}
+			if (option < 4096) {
+				p9_debug(P9_DEBUG_ERROR,
+					 "msize should be at least 4k\n");
+				ret = -EINVAL;
+				continue;
+			}
+			clnt->msize = option;
+			break;
+		case Opt_trans:
+			s = match_strdup(&args[0]);
+			if (!s) {
+				ret = -ENOMEM;
+				p9_debug(P9_DEBUG_ERROR,
+					 "problem allocating copy of trans arg\n");
+				goto free_and_return;
+			}
+
+			v9fs_put_trans(clnt->trans_mod);
+			clnt->trans_mod = v9fs_get_trans_by_name(s);
+			if (!clnt->trans_mod) {
+				pr_info("Could not find request transport: %s\n",
+					s);
+				ret = -EINVAL;
+			}
+			kfree(s);
+			break;
+		case Opt_legacy:
+			clnt->proto_version = p9_proto_legacy;
+			break;
+		case Opt_version:
+			s = match_strdup(&args[0]);
+			if (!s) {
+				ret = -ENOMEM;
+				p9_debug(P9_DEBUG_ERROR,
+					 "problem allocating copy of version arg\n");
+				goto free_and_return;
+			}
+			r = get_protocol_version(s);
+			if (r < 0)
+				ret = r;
+			else
+				clnt->proto_version = r;
+			kfree(s);
+			break;
+		default:
+			continue;
+		}
+	}
+
+free_and_return:
+	if (ret)
+		v9fs_put_trans(clnt->trans_mod);
+	kfree(tmp_options);
+	return ret;
+}
+
+static int p9_fcall_init(struct p9_client *c, struct p9_fcall *fc,
+			 int alloc_msize)
+{
+	if (likely(c->fcall_cache) && alloc_msize == c->msize) {
+		fc->sdata = kmem_cache_alloc(c->fcall_cache, GFP_NOFS);
+		fc->cache = c->fcall_cache;
+	} else {
+		fc->sdata = kmalloc(alloc_msize, GFP_NOFS);
+		fc->cache = NULL;
+	}
+	if (!fc->sdata)
+		return -ENOMEM;
+	fc->capacity = alloc_msize;
+	return 0;
+}
+
+void p9_fcall_fini(struct p9_fcall *fc)
+{
+	/* sdata can be NULL for interrupted requests in trans_rdma,
+	 * and kmem_cache_free does not do NULL-check for us
+	 */
+	if (unlikely(!fc->sdata))
+		return;
+
+	if (fc->cache)
+		kmem_cache_free(fc->cache, fc->sdata);
+	else
+		kfree(fc->sdata);
+}
+EXPORT_SYMBOL(p9_fcall_fini);
+
+static struct kmem_cache *p9_req_cache;
+
+/**
+ * p9_tag_alloc - Allocate a new request.
+ * @c: Client session.
+ * @type: Transaction type.
+ * @t_size: Buffer size for holding this request
+ * (automatic calculation by format template if 0).
+ * @r_size: Buffer size for holding server's reply on this request
+ * (automatic calculation by format template if 0).
+ * @fmt: Format template for assembling 9p request message
+ * (see p9pdu_vwritef).
+ * @ap: Variable arguments to be fed to passed format template
+ * (see p9pdu_vwritef).
+ *
+ * Context: Process context.
+ * Return: Pointer to new request.
+ */
+static struct p9_req_t *
+p9_tag_alloc(struct p9_client *c, int8_t type, uint t_size, uint r_size,
+	      const char *fmt, va_list ap)
+{
+	struct p9_req_t *req = kmem_cache_alloc(p9_req_cache, GFP_NOFS);
+	int alloc_tsize;
+	int alloc_rsize;
+	int tag;
+	va_list apc;
+
+	va_copy(apc, ap);
+	alloc_tsize = min_t(size_t, c->msize,
+			    t_size ?: p9_msg_buf_size(c, type, fmt, apc));
+	va_end(apc);
+
+	alloc_rsize = min_t(size_t, c->msize,
+			    r_size ?: p9_msg_buf_size(c, type + 1, fmt, ap));
+
+	if (!req)
+		return ERR_PTR(-ENOMEM);
+
+	if (p9_fcall_init(c, &req->tc, alloc_tsize))
+		goto free_req;
+	if (p9_fcall_init(c, &req->rc, alloc_rsize))
+		goto free;
+
+	p9pdu_reset(&req->tc);
+	p9pdu_reset(&req->rc);
+	req->t_err = 0;
+	req->status = REQ_STATUS_ALLOC;
+	/* refcount needs to be set to 0 before inserting into the idr
+	 * so p9_tag_lookup does not accept a request that is not fully
+	 * initialized. refcount_set to 2 below will mark request ready.
+	 */
+	refcount_set(&req->refcount, 0);
+	init_waitqueue_head(&req->wq);
+	INIT_LIST_HEAD(&req->req_list);
+
+	idr_preload(GFP_NOFS);
+	spin_lock_irq(&c->lock);
+	if (type == P9_TVERSION)
+		tag = idr_alloc(&c->reqs, req, P9_NOTAG, P9_NOTAG + 1,
+				GFP_NOWAIT);
+	else
+		tag = idr_alloc(&c->reqs, req, 0, P9_NOTAG, GFP_NOWAIT);
+	req->tc.tag = tag;
+	spin_unlock_irq(&c->lock);
+	idr_preload_end();
+	if (tag < 0)
+		goto free;
+
+	/* Init ref to two because in the general case there is one ref
+	 * that is put asynchronously by a writer thread, one ref
+	 * temporarily given by p9_tag_lookup and put by p9_client_cb
+	 * in the recv thread, and one ref put by p9_req_put in the
+	 * main thread. The only exception is virtio that does not use
+	 * p9_tag_lookup but does not have a writer thread either
+	 * (the write happens synchronously in the request/zc_request
+	 * callback), so p9_client_cb eats the second ref there
+	 * as the pointer is duplicated directly by virtqueue_add_sgs()
+	 */
+	refcount_set(&req->refcount, 2);
+
+	return req;
+
+free:
+	p9_fcall_fini(&req->tc);
+	p9_fcall_fini(&req->rc);
+free_req:
+	kmem_cache_free(p9_req_cache, req);
+	return ERR_PTR(-ENOMEM);
+}
+
+/**
+ * p9_tag_lookup - Look up a request by tag.
+ * @c: Client session.
+ * @tag: Transaction ID.
+ *
+ * Context: Any context.
+ * Return: A request, or %NULL if there is no request with that tag.
+ */
+struct p9_req_t *p9_tag_lookup(struct p9_client *c, u16 tag)
+{
+	struct p9_req_t *req;
+
+	rcu_read_lock();
+again:
+	req = idr_find(&c->reqs, tag);
+	if (req) {
+		/* We have to be careful with the req found under rcu_read_lock
+		 * Thanks to SLAB_TYPESAFE_BY_RCU we can safely try to get the
+		 * ref again without corrupting other data, then check again
+		 * that the tag matches once we have the ref
+		 */
+		if (!p9_req_try_get(req))
+			goto again;
+		if (req->tc.tag != tag) {
+			p9_req_put(c, req);
+			goto again;
+		}
+	}
+	rcu_read_unlock();
+
+	return req;
+}
+EXPORT_SYMBOL(p9_tag_lookup);
+
+/**
+ * p9_tag_remove - Remove a tag.
+ * @c: Client session.
+ * @r: Request of reference.
+ *
+ * Context: Any context.
+ */
+static void p9_tag_remove(struct p9_client *c, struct p9_req_t *r)
+{
+	unsigned long flags;
+	u16 tag = r->tc.tag;
+
+	p9_debug(P9_DEBUG_MUX, "freeing clnt %p req %p tag: %d\n", c, r, tag);
+	spin_lock_irqsave(&c->lock, flags);
+	idr_remove(&c->reqs, tag);
+	spin_unlock_irqrestore(&c->lock, flags);
+}
+
+int p9_req_put(struct p9_client *c, struct p9_req_t *r)
+{
+	if (refcount_dec_and_test(&r->refcount)) {
+		p9_tag_remove(c, r);
+
+		p9_fcall_fini(&r->tc);
+		p9_fcall_fini(&r->rc);
+		kmem_cache_free(p9_req_cache, r);
+		return 1;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(p9_req_put);
+
+/**
+ * p9_tag_cleanup - cleans up tags structure and reclaims resources
+ * @c:  v9fs client struct
+ *
+ * This frees resources associated with the tags structure
+ *
+ */
+static void p9_tag_cleanup(struct p9_client *c)
+{
+	struct p9_req_t *req;
+	int id;
+
+	rcu_read_lock();
+	idr_for_each_entry(&c->reqs, req, id) {
+		pr_info("Tag %d still in use\n", id);
+		if (p9_req_put(c, req) == 0)
+			pr_warn("Packet with tag %d has still references",
+				req->tc.tag);
+	}
+	rcu_read_unlock();
+}
+
+/**
+ * p9_client_cb - call back from transport to client
+ * @c: client state
+ * @req: request received
+ * @status: request status, one of REQ_STATUS_*
+ *
+ */
+void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status)
+{
+	p9_debug(P9_DEBUG_MUX, " tag %d\n", req->tc.tag);
+
+	/* This barrier is needed to make sure any change made to req before
+	 * the status change is visible to another thread
+	 */
+	smp_wmb();
+	WRITE_ONCE(req->status, status);
+
+	wake_up(&req->wq);
+	p9_debug(P9_DEBUG_MUX, "wakeup: %d\n", req->tc.tag);
+	p9_req_put(c, req);
+}
+EXPORT_SYMBOL(p9_client_cb);
+
+/**
+ * p9_parse_header - parse header arguments out of a packet
+ * @pdu: packet to parse
+ * @size: size of packet
+ * @type: type of request
+ * @tag: tag of packet
+ * @rewind: set if we need to rewind offset afterwards
+ */
+
+int
+p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
+		int16_t *tag, int rewind)
+{
+	s8 r_type;
+	s16 r_tag;
+	s32 r_size;
+	int offset = pdu->offset;
+	int err;
+
+	pdu->offset = 0;
+
+	err = p9pdu_readf(pdu, 0, "dbw", &r_size, &r_type, &r_tag);
+	if (err)
+		goto rewind_and_exit;
+
+	if (type)
+		*type = r_type;
+	if (tag)
+		*tag = r_tag;
+	if (size)
+		*size = r_size;
+
+	if (pdu->size != r_size || r_size < 7) {
+		err = -EINVAL;
+		goto rewind_and_exit;
+	}
+
+	pdu->id = r_type;
+	pdu->tag = r_tag;
+
+	p9_debug(P9_DEBUG_9P, "<<< size=%d type: %d tag: %d\n",
+		 pdu->size, pdu->id, pdu->tag);
+
+rewind_and_exit:
+	if (rewind)
+		pdu->offset = offset;
+	return err;
+}
+EXPORT_SYMBOL(p9_parse_header);
+
+/**
+ * p9_check_errors - check 9p packet for error return and process it
+ * @c: current client instance
+ * @req: request to parse and check for error conditions
+ *
+ * returns error code if one is discovered, otherwise returns 0
+ *
+ * this will have to be more complicated if we have multiple
+ * error packet types
+ */
+
+static int p9_check_errors(struct p9_client *c, struct p9_req_t *req)
+{
+	s8 type;
+	int err;
+	int ecode;
+
+	err = p9_parse_header(&req->rc, NULL, &type, NULL, 0);
+	if (req->rc.size >= c->msize) {
+		p9_debug(P9_DEBUG_ERROR,
+			 "requested packet size too big: %d\n",
+			 req->rc.size);
+		return -EIO;
+	}
+	/* dump the response from server
+	 * This should be after check errors which poplulate pdu_fcall.
+	 */
+	trace_9p_protocol_dump(c, &req->rc);
+	if (err) {
+		p9_debug(P9_DEBUG_ERROR, "couldn't parse header %d\n", err);
+		return err;
+	}
+	if (type != P9_RERROR && type != P9_RLERROR)
+		return 0;
+
+	if (!p9_is_proto_dotl(c)) {
+		char *ename = NULL;
+
+		err = p9pdu_readf(&req->rc, c->proto_version, "s?d",
+				  &ename, &ecode);
+		if (err) {
+			kfree(ename);
+			goto out_err;
+		}
+
+		if (p9_is_proto_dotu(c) && ecode < 512)
+			err = -ecode;
+
+		if (!err) {
+			err = p9_errstr2errno(ename, strlen(ename));
+
+			p9_debug(P9_DEBUG_9P, "<<< RERROR (%d) %s\n",
+				 -ecode, ename);
+		}
+		kfree(ename);
+	} else {
+		err = p9pdu_readf(&req->rc, c->proto_version, "d", &ecode);
+		if (err)
+			goto out_err;
+		err = -ecode;
+
+		p9_debug(P9_DEBUG_9P, "<<< RLERROR (%d)\n", -ecode);
+	}
+
+	return err;
+
+out_err:
+	p9_debug(P9_DEBUG_ERROR, "couldn't parse error%d\n", err);
+
+	return err;
+}
+
+static struct p9_req_t *
+p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...);
+
+/**
+ * p9_client_flush - flush (cancel) a request
+ * @c: client state
+ * @oldreq: request to cancel
+ *
+ * This sents a flush for a particular request and links
+ * the flush request to the original request.  The current
+ * code only supports a single flush request although the protocol
+ * allows for multiple flush requests to be sent for a single request.
+ *
+ */
+
+static int p9_client_flush(struct p9_client *c, struct p9_req_t *oldreq)
+{
+	struct p9_req_t *req;
+	s16 oldtag;
+	int err;
+
+	err = p9_parse_header(&oldreq->tc, NULL, NULL, &oldtag, 1);
+	if (err)
+		return err;
+
+	p9_debug(P9_DEBUG_9P, ">>> TFLUSH tag %d\n", oldtag);
+
+	req = p9_client_rpc(c, P9_TFLUSH, "w", oldtag);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	/* if we haven't received a response for oldreq,
+	 * remove it from the list
+	 */
+	if (READ_ONCE(oldreq->status) == REQ_STATUS_SENT) {
+		if (c->trans_mod->cancelled)
+			c->trans_mod->cancelled(c, oldreq);
+	}
+
+	p9_req_put(c, req);
+	return 0;
+}
+
+static struct p9_req_t *p9_client_prepare_req(struct p9_client *c,
+					      int8_t type, uint t_size, uint r_size,
+					      const char *fmt, va_list ap)
+{
+	int err;
+	struct p9_req_t *req;
+	va_list apc;
+
+	p9_debug(P9_DEBUG_MUX, "client %p op %d\n", c, type);
+
+	/* we allow for any status other than disconnected */
+	if (c->status == Disconnected)
+		return ERR_PTR(-EIO);
+
+	/* if status is begin_disconnected we allow only clunk request */
+	if (c->status == BeginDisconnect && type != P9_TCLUNK)
+		return ERR_PTR(-EIO);
+
+	va_copy(apc, ap);
+	req = p9_tag_alloc(c, type, t_size, r_size, fmt, apc);
+	va_end(apc);
+	if (IS_ERR(req))
+		return req;
+
+	/* marshall the data */
+	p9pdu_prepare(&req->tc, req->tc.tag, type);
+	err = p9pdu_vwritef(&req->tc, c->proto_version, fmt, ap);
+	if (err)
+		goto reterr;
+	p9pdu_finalize(c, &req->tc);
+	trace_9p_client_req(c, type, req->tc.tag);
+	return req;
+reterr:
+	p9_req_put(c, req);
+	/* We have to put also the 2nd reference as it won't be used */
+	p9_req_put(c, req);
+	return ERR_PTR(err);
+}
+
+/**
+ * p9_client_rpc - issue a request and wait for a response
+ * @c: client session
+ * @type: type of request
+ * @fmt: protocol format string (see protocol.c)
+ *
+ * Returns request structure (which client must free using p9_req_put)
+ */
+
+static struct p9_req_t *
+p9_client_rpc(struct p9_client *c, int8_t type, const char *fmt, ...)
+{
+	va_list ap;
+	int sigpending, err;
+	unsigned long flags;
+	struct p9_req_t *req;
+	/* Passing zero for tsize/rsize to p9_client_prepare_req() tells it to
+	 * auto determine an appropriate (small) request/response size
+	 * according to actual message data being sent. Currently RDMA
+	 * transport is excluded from this response message size optimization,
+	 * as it would not cope with it, due to its pooled response buffers
+	 * (using an optimized request size for RDMA as well though).
+	 */
+	const uint tsize = 0;
+	const uint rsize = c->trans_mod->pooled_rbuffers ? c->msize : 0;
+
+	va_start(ap, fmt);
+	req = p9_client_prepare_req(c, type, tsize, rsize, fmt, ap);
+	va_end(ap);
+	if (IS_ERR(req))
+		return req;
+
+	if (signal_pending(current)) {
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+	} else {
+		sigpending = 0;
+	}
+
+	err = c->trans_mod->request(c, req);
+	if (err < 0) {
+		/* write won't happen */
+		p9_req_put(c, req);
+		if (err != -ERESTARTSYS && err != -EFAULT)
+			c->status = Disconnected;
+		goto recalc_sigpending;
+	}
+again:
+	/* Wait for the response */
+	err = wait_event_killable(req->wq,
+				  READ_ONCE(req->status) >= REQ_STATUS_RCVD);
+
+	/* Make sure our req is coherent with regard to updates in other
+	 * threads - echoes to wmb() in the callback
+	 */
+	smp_rmb();
+
+	if (err == -ERESTARTSYS && c->status == Connected &&
+	    type == P9_TFLUSH) {
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+		goto again;
+	}
+
+	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
+		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
+		err = req->t_err;
+	}
+	if (err == -ERESTARTSYS && c->status == Connected) {
+		p9_debug(P9_DEBUG_MUX, "flushing\n");
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+
+		if (c->trans_mod->cancel(c, req))
+			p9_client_flush(c, req);
+
+		/* if we received the response anyway, don't signal error */
+		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
+			err = 0;
+	}
+recalc_sigpending:
+	if (sigpending) {
+		spin_lock_irqsave(&current->sighand->siglock, flags);
+		recalc_sigpending();
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	}
+	if (err < 0)
+		goto reterr;
+
+	err = p9_check_errors(c, req);
+	trace_9p_client_res(c, type, req->rc.tag, err);
+	if (!err)
+		return req;
+reterr:
+	p9_req_put(c, req);
+	return ERR_PTR(safe_errno(err));
+}
+
+/**
+ * p9_client_zc_rpc - issue a request and wait for a response
+ * @c: client session
+ * @type: type of request
+ * @uidata: destination for zero copy read
+ * @uodata: source for zero copy write
+ * @inlen: read buffer size
+ * @olen: write buffer size
+ * @in_hdrlen: reader header size, This is the size of response protocol data
+ * @fmt: protocol format string (see protocol.c)
+ *
+ * Returns request structure (which client must free using p9_req_put)
+ */
+static struct p9_req_t *p9_client_zc_rpc(struct p9_client *c, int8_t type,
+					 struct iov_iter *uidata,
+					 struct iov_iter *uodata,
+					 int inlen, int olen, int in_hdrlen,
+					 const char *fmt, ...)
+{
+	va_list ap;
+	int sigpending, err;
+	unsigned long flags;
+	struct p9_req_t *req;
+
+	va_start(ap, fmt);
+	/* We allocate a inline protocol data of only 4k bytes.
+	 * The actual content is passed in zero-copy fashion.
+	 */
+	req = p9_client_prepare_req(c, type, P9_ZC_HDR_SZ, P9_ZC_HDR_SZ, fmt, ap);
+	va_end(ap);
+	if (IS_ERR(req))
+		return req;
+
+	if (signal_pending(current)) {
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+	} else {
+		sigpending = 0;
+	}
+
+	err = c->trans_mod->zc_request(c, req, uidata, uodata,
+				       inlen, olen, in_hdrlen);
+	if (err < 0) {
+		if (err == -EIO)
+			c->status = Disconnected;
+		if (err != -ERESTARTSYS)
+			goto recalc_sigpending;
+	}
+	if (READ_ONCE(req->status) == REQ_STATUS_ERROR) {
+		p9_debug(P9_DEBUG_ERROR, "req_status error %d\n", req->t_err);
+		err = req->t_err;
+	}
+	if (err == -ERESTARTSYS && c->status == Connected) {
+		p9_debug(P9_DEBUG_MUX, "flushing\n");
+		sigpending = 1;
+		clear_thread_flag(TIF_SIGPENDING);
+
+		if (c->trans_mod->cancel(c, req))
+			p9_client_flush(c, req);
+
+		/* if we received the response anyway, don't signal error */
+		if (READ_ONCE(req->status) == REQ_STATUS_RCVD)
+			err = 0;
+	}
+recalc_sigpending:
+	if (sigpending) {
+		spin_lock_irqsave(&current->sighand->siglock, flags);
+		recalc_sigpending();
+		spin_unlock_irqrestore(&current->sighand->siglock, flags);
+	}
+	if (err < 0)
+		goto reterr;
+
+	err = p9_check_errors(c, req);
+	trace_9p_client_res(c, type, req->rc.tag, err);
+	if (!err)
+		return req;
+reterr:
+	p9_req_put(c, req);
+	return ERR_PTR(safe_errno(err));
+}
+
+static struct p9_fid *p9_fid_create(struct p9_client *clnt)
+{
+	int ret;
+	struct p9_fid *fid;
+
+	p9_debug(P9_DEBUG_FID, "clnt %p\n", clnt);
+	fid = kzalloc(sizeof(*fid), GFP_KERNEL);
+	if (!fid)
+		return NULL;
+
+	fid->mode = -1;
+	fid->uid = current_fsuid();
+	fid->clnt = clnt;
+	refcount_set(&fid->count, 1);
+
+	idr_preload(GFP_KERNEL);
+	spin_lock_irq(&clnt->lock);
+	ret = idr_alloc_u32(&clnt->fids, fid, &fid->fid, P9_NOFID - 1,
+			    GFP_NOWAIT);
+	spin_unlock_irq(&clnt->lock);
+	idr_preload_end();
+	if (!ret) {
+		trace_9p_fid_ref(fid, P9_FID_REF_CREATE);
+		return fid;
+	}
+
+	kfree(fid);
+	return NULL;
+}
+
+static void p9_fid_destroy(struct p9_fid *fid)
+{
+	struct p9_client *clnt;
+	unsigned long flags;
+
+	p9_debug(P9_DEBUG_FID, "fid %d\n", fid->fid);
+	trace_9p_fid_ref(fid, P9_FID_REF_DESTROY);
+	clnt = fid->clnt;
+	spin_lock_irqsave(&clnt->lock, flags);
+	idr_remove(&clnt->fids, fid->fid);
+	spin_unlock_irqrestore(&clnt->lock, flags);
+	kfree(fid->rdir);
+	kfree(fid);
+}
+
+/* We also need to export tracepoint symbols for tracepoint_enabled() */
+EXPORT_TRACEPOINT_SYMBOL(9p_fid_ref);
+
+void do_trace_9p_fid_get(struct p9_fid *fid)
+{
+	trace_9p_fid_ref(fid, P9_FID_REF_GET);
+}
+EXPORT_SYMBOL(do_trace_9p_fid_get);
+
+void do_trace_9p_fid_put(struct p9_fid *fid)
+{
+	trace_9p_fid_ref(fid, P9_FID_REF_PUT);
+}
+EXPORT_SYMBOL(do_trace_9p_fid_put);
+
+static int p9_client_version(struct p9_client *c)
+{
+	int err = 0;
+	struct p9_req_t *req;
+	char *version = NULL;
+	int msize;
+
+	p9_debug(P9_DEBUG_9P, ">>> TVERSION msize %d protocol %d\n",
+		 c->msize, c->proto_version);
+
+	switch (c->proto_version) {
+	case p9_proto_2000L:
+		req = p9_client_rpc(c, P9_TVERSION, "ds",
+				    c->msize, "9P2000.L");
+		break;
+	case p9_proto_2000u:
+		req = p9_client_rpc(c, P9_TVERSION, "ds",
+				    c->msize, "9P2000.u");
+		break;
+	case p9_proto_legacy:
+		req = p9_client_rpc(c, P9_TVERSION, "ds",
+				    c->msize, "9P2000");
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	err = p9pdu_readf(&req->rc, c->proto_version, "ds", &msize, &version);
+	if (err) {
+		p9_debug(P9_DEBUG_9P, "version error %d\n", err);
+		trace_9p_protocol_dump(c, &req->rc);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RVERSION msize %d %s\n", msize, version);
+	if (!strncmp(version, "9P2000.L", 8)) {
+		c->proto_version = p9_proto_2000L;
+	} else if (!strncmp(version, "9P2000.u", 8)) {
+		c->proto_version = p9_proto_2000u;
+	} else if (!strncmp(version, "9P2000", 6)) {
+		c->proto_version = p9_proto_legacy;
+	} else {
+		p9_debug(P9_DEBUG_ERROR,
+			 "server returned an unknown version: %s\n", version);
+		err = -EREMOTEIO;
+		goto error;
+	}
+
+	if (msize < 4096) {
+		p9_debug(P9_DEBUG_ERROR,
+			 "server returned a msize < 4096: %d\n", msize);
+		err = -EREMOTEIO;
+		goto error;
+	}
+	if (msize < c->msize)
+		c->msize = msize;
+
+error:
+	kfree(version);
+	p9_req_put(c, req);
+
+	return err;
+}
+
+struct p9_client *p9_client_create(const char *dev_name, char *options)
+{
+	int err;
+	struct p9_client *clnt;
+	char *client_id;
+
+	err = 0;
+	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
+	if (!clnt)
+		return ERR_PTR(-ENOMEM);
+
+	clnt->trans_mod = NULL;
+	clnt->trans = NULL;
+	clnt->fcall_cache = NULL;
+
+	client_id = utsname()->nodename;
+	memcpy(clnt->name, client_id, strlen(client_id) + 1);
+
+	spin_lock_init(&clnt->lock);
+	idr_init(&clnt->fids);
+	idr_init(&clnt->reqs);
+
+	err = parse_opts(options, clnt);
+	if (err < 0)
+		goto free_client;
+
+	if (!clnt->trans_mod)
+		clnt->trans_mod = v9fs_get_default_trans();
+
+	if (!clnt->trans_mod) {
+		err = -EPROTONOSUPPORT;
+		p9_debug(P9_DEBUG_ERROR,
+			 "No transport defined or default transport\n");
+		goto free_client;
+	}
+
+	p9_debug(P9_DEBUG_MUX, "clnt %p trans %p msize %d protocol %d\n",
+		 clnt, clnt->trans_mod, clnt->msize, clnt->proto_version);
+
+	err = clnt->trans_mod->create(clnt, dev_name, options);
+	if (err)
+		goto put_trans;
+
+	if (clnt->msize > clnt->trans_mod->maxsize) {
+		clnt->msize = clnt->trans_mod->maxsize;
+		pr_info("Limiting 'msize' to %d as this is the maximum "
+			"supported by transport %s\n",
+			clnt->msize, clnt->trans_mod->name
+		);
+	}
+
+	if (clnt->msize < 4096) {
+		p9_debug(P9_DEBUG_ERROR,
+			 "Please specify a msize of at least 4k\n");
+		err = -EINVAL;
+		goto close_trans;
+	}
+
+	err = p9_client_version(clnt);
+	if (err)
+		goto close_trans;
+
+	/* P9_HDRSZ + 4 is the smallest packet header we can have that is
+	 * followed by data accessed from userspace by read
+	 */
+	clnt->fcall_cache =
+		kmem_cache_create_usercopy("9p-fcall-cache", clnt->msize,
+					   0, 0, P9_HDRSZ + 4,
+					   clnt->msize - (P9_HDRSZ + 4),
+					   NULL);
+
+	return clnt;
+
+close_trans:
+	clnt->trans_mod->close(clnt);
+put_trans:
+	v9fs_put_trans(clnt->trans_mod);
+free_client:
+	kfree(clnt);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_create);
+
+void p9_client_destroy(struct p9_client *clnt)
+{
+	struct p9_fid *fid;
+	int id;
+
+	p9_debug(P9_DEBUG_MUX, "clnt %p\n", clnt);
+
+	if (clnt->trans_mod)
+		clnt->trans_mod->close(clnt);
+
+	v9fs_put_trans(clnt->trans_mod);
+
+	idr_for_each_entry(&clnt->fids, fid, id) {
+		pr_info("Found fid %d not clunked\n", fid->fid);
+		p9_fid_destroy(fid);
+	}
+
+	p9_tag_cleanup(clnt);
+
+	kmem_cache_destroy(clnt->fcall_cache);
+	kfree(clnt);
+}
+EXPORT_SYMBOL(p9_client_destroy);
+
+void p9_client_disconnect(struct p9_client *clnt)
+{
+	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
+	clnt->status = Disconnected;
+}
+EXPORT_SYMBOL(p9_client_disconnect);
+
+void p9_client_begin_disconnect(struct p9_client *clnt)
+{
+	p9_debug(P9_DEBUG_9P, "clnt %p\n", clnt);
+	clnt->status = BeginDisconnect;
+}
+EXPORT_SYMBOL(p9_client_begin_disconnect);
+
+struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
+				const char *uname, kuid_t n_uname,
+				const char *aname)
+{
+	int err = 0;
+	struct p9_req_t *req;
+	struct p9_fid *fid;
+	struct p9_qid qid;
+
+	p9_debug(P9_DEBUG_9P, ">>> TATTACH afid %d uname %s aname %s\n",
+		 afid ? afid->fid : -1, uname, aname);
+	fid = p9_fid_create(clnt);
+	if (!fid) {
+		err = -ENOMEM;
+		goto error;
+	}
+	fid->uid = n_uname;
+
+	req = p9_client_rpc(clnt, P9_TATTACH, "ddss?u", fid->fid,
+			    afid ? afid->fid : P9_NOFID, uname, aname, n_uname);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", &qid);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		p9_req_put(clnt, req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RATTACH qid %x.%llx.%x\n",
+		 qid.type, qid.path, qid.version);
+
+	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
+
+	p9_req_put(clnt, req);
+	return fid;
+
+error:
+	if (fid)
+		p9_fid_destroy(fid);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_attach);
+
+struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
+			      const unsigned char * const *wnames, int clone)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_fid *fid;
+	struct p9_qid *wqids;
+	struct p9_req_t *req;
+	u16 nwqids, count;
+
+	err = 0;
+	wqids = NULL;
+	clnt = oldfid->clnt;
+	if (clone) {
+		fid = p9_fid_create(clnt);
+		if (!fid) {
+			err = -ENOMEM;
+			goto error;
+		}
+
+		fid->uid = oldfid->uid;
+	} else {
+		fid = oldfid;
+	}
+
+	p9_debug(P9_DEBUG_9P, ">>> TWALK fids %d,%d nwname %ud wname[0] %s\n",
+		 oldfid->fid, fid->fid, nwname, wnames ? wnames[0] : NULL);
+	req = p9_client_rpc(clnt, P9_TWALK, "ddT", oldfid->fid, fid->fid,
+			    nwname, wnames);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "R", &nwqids, &wqids);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		p9_req_put(clnt, req);
+		goto clunk_fid;
+	}
+	p9_req_put(clnt, req);
+
+	p9_debug(P9_DEBUG_9P, "<<< RWALK nwqid %d:\n", nwqids);
+
+	if (nwqids != nwname) {
+		err = -ENOENT;
+		goto clunk_fid;
+	}
+
+	for (count = 0; count < nwqids; count++)
+		p9_debug(P9_DEBUG_9P, "<<<     [%d] %x.%llx.%x\n",
+			 count, wqids[count].type,
+			 wqids[count].path,
+			 wqids[count].version);
+
+	if (nwname)
+		memmove(&fid->qid, &wqids[nwqids - 1], sizeof(struct p9_qid));
+	else
+		memmove(&fid->qid, &oldfid->qid, sizeof(struct p9_qid));
+
+	kfree(wqids);
+	return fid;
+
+clunk_fid:
+	kfree(wqids);
+	p9_fid_put(fid);
+	fid = NULL;
+
+error:
+	if (fid && fid != oldfid)
+		p9_fid_destroy(fid);
+
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_walk);
+
+int p9_client_open(struct p9_fid *fid, int mode)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+	struct p9_qid qid;
+	int iounit;
+
+	clnt = fid->clnt;
+	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
+		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
+	err = 0;
+
+	if (fid->mode != -1)
+		return -EINVAL;
+
+	if (p9_is_proto_dotl(clnt))
+		req = p9_client_rpc(clnt, P9_TLOPEN, "dd", fid->fid, mode);
+	else
+		req = p9_client_rpc(clnt, P9_TOPEN, "db", fid->fid, mode);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto free_and_error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< %s qid %x.%llx.%x iounit %x\n",
+		 p9_is_proto_dotl(clnt) ? "RLOPEN" : "ROPEN",  qid.type,
+		 qid.path, qid.version, iounit);
+
+	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
+	fid->mode = mode;
+	fid->iounit = iounit;
+
+free_and_error:
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_open);
+
+int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
+			  u32 mode, kgid_t gid, struct p9_qid *qid)
+{
+	int err = 0;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+	int iounit;
+
+	p9_debug(P9_DEBUG_9P,
+		 ">>> TLCREATE fid %d name %s flags %d mode %d gid %d\n",
+		 ofid->fid, name, flags, mode,
+		 from_kgid(&init_user_ns, gid));
+	clnt = ofid->clnt;
+
+	if (ofid->mode != -1)
+		return -EINVAL;
+
+	req = p9_client_rpc(clnt, P9_TLCREATE, "dsddg", ofid->fid, name, flags,
+			    mode, gid);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", qid, &iounit);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto free_and_error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RLCREATE qid %x.%llx.%x iounit %x\n",
+		 qid->type, qid->path, qid->version, iounit);
+
+	memmove(&ofid->qid, qid, sizeof(struct p9_qid));
+	ofid->mode = flags;
+	ofid->iounit = iounit;
+
+free_and_error:
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_create_dotl);
+
+int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
+		     char *extension)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+	struct p9_qid qid;
+	int iounit;
+
+	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
+		 fid->fid, name, perm, mode);
+	err = 0;
+	clnt = fid->clnt;
+
+	if (fid->mode != -1)
+		return -EINVAL;
+
+	req = p9_client_rpc(clnt, P9_TCREATE, "dsdb?s", fid->fid, name, perm,
+			    mode, extension);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "Qd", &qid, &iounit);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto free_and_error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RCREATE qid %x.%llx.%x iounit %x\n",
+		 qid.type, qid.path, qid.version, iounit);
+
+	memmove(&fid->qid, &qid, sizeof(struct p9_qid));
+	fid->mode = mode;
+	fid->iounit = iounit;
+
+free_and_error:
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_fcreate);
+
+int p9_client_symlink(struct p9_fid *dfid, const char *name,
+		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
+{
+	int err = 0;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	p9_debug(P9_DEBUG_9P, ">>> TSYMLINK dfid %d name %s  symtgt %s\n",
+		 dfid->fid, name, symtgt);
+	clnt = dfid->clnt;
+
+	req = p9_client_rpc(clnt, P9_TSYMLINK, "dssg", dfid->fid, name, symtgt,
+			    gid);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto free_and_error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RSYMLINK qid %x.%llx.%x\n",
+		 qid->type, qid->path, qid->version);
+
+free_and_error:
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_symlink);
+
+int p9_client_link(struct p9_fid *dfid, struct p9_fid *oldfid, const char *newname)
+{
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	p9_debug(P9_DEBUG_9P, ">>> TLINK dfid %d oldfid %d newname %s\n",
+		 dfid->fid, oldfid->fid, newname);
+	clnt = dfid->clnt;
+	req = p9_client_rpc(clnt, P9_TLINK, "dds", dfid->fid, oldfid->fid,
+			    newname);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	p9_debug(P9_DEBUG_9P, "<<< RLINK\n");
+	p9_req_put(clnt, req);
+	return 0;
+}
+EXPORT_SYMBOL(p9_client_link);
+
+int p9_client_fsync(struct p9_fid *fid, int datasync)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
+		 fid->fid, datasync);
+	err = 0;
+	clnt = fid->clnt;
+
+	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RFSYNC fid %d\n", fid->fid);
+
+	p9_req_put(clnt, req);
+
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_fsync);
+
+int p9_client_clunk(struct p9_fid *fid)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+	int retries = 0;
+
+again:
+	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
+		 fid->fid, retries);
+	err = 0;
+	clnt = fid->clnt;
+
+	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RCLUNK fid %d\n", fid->fid);
+
+	p9_req_put(clnt, req);
+error:
+	/* Fid is not valid even after a failed clunk
+	 * If interrupted, retry once then give up and
+	 * leak fid until umount.
+	 */
+	if (err == -ERESTARTSYS) {
+		if (retries++ == 0)
+			goto again;
+	} else {
+		p9_fid_destroy(fid);
+	}
+	return err;
+}
+EXPORT_SYMBOL(p9_client_clunk);
+
+int p9_client_remove(struct p9_fid *fid)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
+	err = 0;
+	clnt = fid->clnt;
+
+	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RREMOVE fid %d\n", fid->fid);
+
+	p9_req_put(clnt, req);
+error:
+	if (err == -ERESTARTSYS)
+		p9_fid_put(fid);
+	else
+		p9_fid_destroy(fid);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_remove);
+
+int p9_client_unlinkat(struct p9_fid *dfid, const char *name, int flags)
+{
+	int err = 0;
+	struct p9_req_t *req;
+	struct p9_client *clnt;
+
+	p9_debug(P9_DEBUG_9P, ">>> TUNLINKAT fid %d %s %d\n",
+		 dfid->fid, name, flags);
+
+	clnt = dfid->clnt;
+	req = p9_client_rpc(clnt, P9_TUNLINKAT, "dsd", dfid->fid, name, flags);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P, "<<< RUNLINKAT fid %d %s\n", dfid->fid, name);
+
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_unlinkat);
+
+int
+p9_client_read(struct p9_fid *fid, u64 offset, struct iov_iter *to, int *err)
+{
+	int total = 0;
+	*err = 0;
+
+	while (iov_iter_count(to)) {
+		int count;
+
+		count = p9_client_read_once(fid, offset, to, err);
+		if (!count || *err)
+			break;
+		offset += count;
+		total += count;
+	}
+	return total;
+}
+EXPORT_SYMBOL(p9_client_read);
+
+int
+p9_client_read_once(struct p9_fid *fid, u64 offset, struct iov_iter *to,
+		    int *err)
+{
+	struct p9_client *clnt = fid->clnt;
+	struct p9_req_t *req;
+	int count = iov_iter_count(to);
+	int rsize, received, non_zc = 0;
+	char *dataptr;
+
+	*err = 0;
+	p9_debug(P9_DEBUG_9P, ">>> TREAD fid %d offset %llu %zu\n",
+		 fid->fid, offset, iov_iter_count(to));
+
+	rsize = fid->iounit;
+	if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
+		rsize = clnt->msize - P9_IOHDRSZ;
+
+	if (count < rsize)
+		rsize = count;
+
+	/* Don't bother zerocopy for small IO (< 1024) */
+	if (clnt->trans_mod->zc_request && rsize > 1024) {
+		/* response header len is 11
+		 * PDU Header(7) + IO Size (4)
+		 */
+		req = p9_client_zc_rpc(clnt, P9_TREAD, to, NULL, rsize,
+				       0, 11, "dqd", fid->fid,
+				       offset, rsize);
+	} else {
+		non_zc = 1;
+		req = p9_client_rpc(clnt, P9_TREAD, "dqd", fid->fid, offset,
+				    rsize);
+	}
+	if (IS_ERR(req)) {
+		*err = PTR_ERR(req);
+		if (!non_zc)
+			iov_iter_revert(to, count - iov_iter_count(to));
+		return 0;
+	}
+
+	*err = p9pdu_readf(&req->rc, clnt->proto_version,
+			   "D", &received, &dataptr);
+	if (*err) {
+		if (!non_zc)
+			iov_iter_revert(to, count - iov_iter_count(to));
+		trace_9p_protocol_dump(clnt, &req->rc);
+		p9_req_put(clnt, req);
+		return 0;
+	}
+	if (rsize < received) {
+		pr_err("bogus RREAD count (%d > %d)\n", received, rsize);
+		received = rsize;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RREAD count %d\n", count);
+
+	if (non_zc) {
+		int n = copy_to_iter(dataptr, received, to);
+
+		if (n != received) {
+			*err = -EFAULT;
+			p9_req_put(clnt, req);
+			return n;
+		}
+	} else {
+		iov_iter_revert(to, count - received - iov_iter_count(to));
+	}
+	p9_req_put(clnt, req);
+	return received;
+}
+EXPORT_SYMBOL(p9_client_read_once);
+
+int
+p9_client_write(struct p9_fid *fid, u64 offset, struct iov_iter *from, int *err)
+{
+	struct p9_client *clnt = fid->clnt;
+	struct p9_req_t *req;
+	int total = 0;
+	*err = 0;
+
+	p9_debug(P9_DEBUG_9P, ">>> TWRITE fid %d offset %llu count %zd\n",
+		 fid->fid, offset, iov_iter_count(from));
+
+	while (iov_iter_count(from)) {
+		int count = iov_iter_count(from);
+		int rsize = fid->iounit;
+		int written;
+
+		if (!rsize || rsize > clnt->msize - P9_IOHDRSZ)
+			rsize = clnt->msize - P9_IOHDRSZ;
+
+		if (count < rsize)
+			rsize = count;
+
+		/* Don't bother zerocopy for small IO (< 1024) */
+		if (clnt->trans_mod->zc_request && rsize > 1024) {
+			req = p9_client_zc_rpc(clnt, P9_TWRITE, NULL, from, 0,
+					       rsize, P9_ZC_HDR_SZ, "dqd",
+					       fid->fid, offset, rsize);
+		} else {
+			req = p9_client_rpc(clnt, P9_TWRITE, "dqV", fid->fid,
+					    offset, rsize, from);
+		}
+		if (IS_ERR(req)) {
+			iov_iter_revert(from, count - iov_iter_count(from));
+			*err = PTR_ERR(req);
+			break;
+		}
+
+		*err = p9pdu_readf(&req->rc, clnt->proto_version, "d", &written);
+		if (*err) {
+			iov_iter_revert(from, count - iov_iter_count(from));
+			trace_9p_protocol_dump(clnt, &req->rc);
+			p9_req_put(clnt, req);
+			break;
+		}
+		if (rsize < written) {
+			pr_err("bogus RWRITE count (%d > %d)\n", written, rsize);
+			written = rsize;
+		}
+
+		p9_debug(P9_DEBUG_9P, "<<< RWRITE count %d\n", count);
+
+		p9_req_put(clnt, req);
+		iov_iter_revert(from, count - written - iov_iter_count(from));
+		total += written;
+		offset += written;
+	}
+	return total;
+}
+EXPORT_SYMBOL(p9_client_write);
+
+struct p9_wstat *p9_client_stat(struct p9_fid *fid)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_wstat *ret;
+	struct p9_req_t *req;
+	u16 ignored;
+
+	p9_debug(P9_DEBUG_9P, ">>> TSTAT fid %d\n", fid->fid);
+
+	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
+	if (!ret)
+		return ERR_PTR(-ENOMEM);
+
+	err = 0;
+	clnt = fid->clnt;
+
+	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "wS", &ignored, ret);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		p9_req_put(clnt, req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P,
+		 "<<< RSTAT sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
+		 "<<<    mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
+		 "<<<    name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
+		 "<<<    uid=%d gid=%d n_muid=%d\n",
+		 ret->size, ret->type, ret->dev, ret->qid.type, ret->qid.path,
+		 ret->qid.version, ret->mode,
+		 ret->atime, ret->mtime, ret->length,
+		 ret->name, ret->uid, ret->gid, ret->muid, ret->extension,
+		 from_kuid(&init_user_ns, ret->n_uid),
+		 from_kgid(&init_user_ns, ret->n_gid),
+		 from_kuid(&init_user_ns, ret->n_muid));
+
+	p9_req_put(clnt, req);
+	return ret;
+
+error:
+	kfree(ret);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_stat);
+
+struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
+					    u64 request_mask)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_stat_dotl *ret;
+	struct p9_req_t *req;
+
+	p9_debug(P9_DEBUG_9P, ">>> TGETATTR fid %d, request_mask %lld\n",
+		 fid->fid, request_mask);
+
+	ret = kmalloc(sizeof(*ret), GFP_KERNEL);
+	if (!ret)
+		return ERR_PTR(-ENOMEM);
+
+	err = 0;
+	clnt = fid->clnt;
+
+	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "A", ret);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		p9_req_put(clnt, req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RGETATTR st_result_mask=%lld\n"
+		 "<<< qid=%x.%llx.%x\n"
+		 "<<< st_mode=%8.8x st_nlink=%llu\n"
+		 "<<< st_uid=%d st_gid=%d\n"
+		 "<<< st_rdev=%llx st_size=%llx st_blksize=%llu st_blocks=%llu\n"
+		 "<<< st_atime_sec=%lld st_atime_nsec=%lld\n"
+		 "<<< st_mtime_sec=%lld st_mtime_nsec=%lld\n"
+		 "<<< st_ctime_sec=%lld st_ctime_nsec=%lld\n"
+		 "<<< st_btime_sec=%lld st_btime_nsec=%lld\n"
+		 "<<< st_gen=%lld st_data_version=%lld\n",
+		 ret->st_result_mask,
+		 ret->qid.type, ret->qid.path, ret->qid.version,
+		 ret->st_mode, ret->st_nlink,
+		 from_kuid(&init_user_ns, ret->st_uid),
+		 from_kgid(&init_user_ns, ret->st_gid),
+		 ret->st_rdev, ret->st_size, ret->st_blksize, ret->st_blocks,
+		 ret->st_atime_sec, ret->st_atime_nsec,
+		 ret->st_mtime_sec, ret->st_mtime_nsec,
+		 ret->st_ctime_sec, ret->st_ctime_nsec,
+		 ret->st_btime_sec, ret->st_btime_nsec,
+		 ret->st_gen, ret->st_data_version);
+
+	p9_req_put(clnt, req);
+	return ret;
+
+error:
+	kfree(ret);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(p9_client_getattr_dotl);
+
+static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
+{
+	int ret;
+
+	/* NOTE: size shouldn't include its own length */
+	/* size[2] type[2] dev[4] qid[13] */
+	/* mode[4] atime[4] mtime[4] length[8]*/
+	/* name[s] uid[s] gid[s] muid[s] */
+	ret = 2 + 4 + 13 + 4 + 4 + 4 + 8 + 2 + 2 + 2 + 2;
+
+	if (wst->name)
+		ret += strlen(wst->name);
+	if (wst->uid)
+		ret += strlen(wst->uid);
+	if (wst->gid)
+		ret += strlen(wst->gid);
+	if (wst->muid)
+		ret += strlen(wst->muid);
+
+	if (proto_version == p9_proto_2000u ||
+	    proto_version == p9_proto_2000L) {
+		/* extension[s] n_uid[4] n_gid[4] n_muid[4] */
+		ret += 2 + 4 + 4 + 4;
+		if (wst->extension)
+			ret += strlen(wst->extension);
+	}
+
+	return ret;
+}
+
+int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
+{
+	int err;
+	struct p9_req_t *req;
+	struct p9_client *clnt;
+
+	err = 0;
+	clnt = fid->clnt;
+	wst->size = p9_client_statsize(wst, clnt->proto_version);
+	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
+		 fid->fid);
+	p9_debug(P9_DEBUG_9P,
+		 "     sz=%x type=%x dev=%x qid=%x.%llx.%x\n"
+		 "     mode=%8.8x atime=%8.8x mtime=%8.8x length=%llx\n"
+		 "     name=%s uid=%s gid=%s muid=%s extension=(%s)\n"
+		 "     uid=%d gid=%d n_muid=%d\n",
+		 wst->size, wst->type, wst->dev, wst->qid.type,
+		 wst->qid.path, wst->qid.version,
+		 wst->mode, wst->atime, wst->mtime, wst->length,
+		 wst->name, wst->uid, wst->gid, wst->muid, wst->extension,
+		 from_kuid(&init_user_ns, wst->n_uid),
+		 from_kgid(&init_user_ns, wst->n_gid),
+		 from_kuid(&init_user_ns, wst->n_muid));
+
+	req = p9_client_rpc(clnt, P9_TWSTAT, "dwS",
+			    fid->fid, wst->size + 2, wst);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RWSTAT fid %d\n", fid->fid);
+
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_wstat);
+
+int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
+{
+	int err;
+	struct p9_req_t *req;
+	struct p9_client *clnt;
+
+	err = 0;
+	clnt = fid->clnt;
+	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
+	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
+		 p9attr->valid, p9attr->mode,
+		 from_kuid(&init_user_ns, p9attr->uid),
+		 from_kgid(&init_user_ns, p9attr->gid),
+		 p9attr->size);
+	p9_debug(P9_DEBUG_9P, "    atime_sec=%lld atime_nsec=%lld\n",
+		 p9attr->atime_sec, p9attr->atime_nsec);
+	p9_debug(P9_DEBUG_9P, "    mtime_sec=%lld mtime_nsec=%lld\n",
+		 p9attr->mtime_sec, p9attr->mtime_nsec);
+
+	req = p9_client_rpc(clnt, P9_TSETATTR, "dI", fid->fid, p9attr);
+
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P, "<<< RSETATTR fid %d\n", fid->fid);
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_setattr);
+
+int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
+{
+	int err;
+	struct p9_req_t *req;
+	struct p9_client *clnt;
+
+	err = 0;
+	clnt = fid->clnt;
+
+	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
+
+	req = p9_client_rpc(clnt, P9_TSTATFS, "d", fid->fid);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "ddqqqqqqd", &sb->type,
+			  &sb->bsize, &sb->blocks, &sb->bfree, &sb->bavail,
+			  &sb->files, &sb->ffree, &sb->fsid, &sb->namelen);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		p9_req_put(clnt, req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P,
+		 "<<< RSTATFS fid %d type 0x%x bsize %u blocks %llu bfree %llu bavail %llu files %llu ffree %llu fsid %llu namelen %u\n",
+		 fid->fid, sb->type, sb->bsize, sb->blocks, sb->bfree,
+		 sb->bavail, sb->files, sb->ffree, sb->fsid, sb->namelen);
+
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_statfs);
+
+int p9_client_rename(struct p9_fid *fid,
+		     struct p9_fid *newdirfid, const char *name)
+{
+	int err;
+	struct p9_req_t *req;
+	struct p9_client *clnt;
+
+	err = 0;
+	clnt = fid->clnt;
+
+	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
+		 fid->fid, newdirfid->fid, name);
+
+	req = p9_client_rpc(clnt, P9_TRENAME, "dds", fid->fid,
+			    newdirfid->fid, name);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RRENAME fid %d\n", fid->fid);
+
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_rename);
+
+int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
+		       struct p9_fid *newdirfid, const char *new_name)
+{
+	int err;
+	struct p9_req_t *req;
+	struct p9_client *clnt;
+
+	err = 0;
+	clnt = olddirfid->clnt;
+
+	p9_debug(P9_DEBUG_9P,
+		 ">>> TRENAMEAT olddirfid %d old name %s newdirfid %d new name %s\n",
+		 olddirfid->fid, old_name, newdirfid->fid, new_name);
+
+	req = p9_client_rpc(clnt, P9_TRENAMEAT, "dsds", olddirfid->fid,
+			    old_name, newdirfid->fid, new_name);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RRENAMEAT newdirfid %d new name %s\n",
+		 newdirfid->fid, new_name);
+
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_renameat);
+
+/* An xattrwalk without @attr_name gives the fid for the lisxattr namespace
+ */
+struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
+				   const char *attr_name, u64 *attr_size)
+{
+	int err;
+	struct p9_req_t *req;
+	struct p9_client *clnt;
+	struct p9_fid *attr_fid;
+
+	err = 0;
+	clnt = file_fid->clnt;
+	attr_fid = p9_fid_create(clnt);
+	if (!attr_fid) {
+		err = -ENOMEM;
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P,
+		 ">>> TXATTRWALK file_fid %d, attr_fid %d name '%s'\n",
+		 file_fid->fid, attr_fid->fid, attr_name);
+
+	req = p9_client_rpc(clnt, P9_TXATTRWALK, "dds",
+			    file_fid->fid, attr_fid->fid, attr_name);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "q", attr_size);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		p9_req_put(clnt, req);
+		goto clunk_fid;
+	}
+	p9_req_put(clnt, req);
+	p9_debug(P9_DEBUG_9P, "<<<  RXATTRWALK fid %d size %llu\n",
+		 attr_fid->fid, *attr_size);
+	return attr_fid;
+clunk_fid:
+	p9_fid_put(attr_fid);
+	attr_fid = NULL;
+error:
+	if (attr_fid && attr_fid != file_fid)
+		p9_fid_destroy(attr_fid);
+
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
+
+int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
+			  u64 attr_size, int flags)
+{
+	int err;
+	struct p9_req_t *req;
+	struct p9_client *clnt;
+
+	p9_debug(P9_DEBUG_9P,
+		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
+		 fid->fid, name, attr_size, flags);
+	err = 0;
+	clnt = fid->clnt;
+	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
+			    fid->fid, name, attr_size, flags);
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P, "<<< RXATTRCREATE fid %d\n", fid->fid);
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL_GPL(p9_client_xattrcreate);
+
+int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
+{
+	int err, rsize, non_zc = 0;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+	char *dataptr;
+	struct kvec kv = {.iov_base = data, .iov_len = count};
+	struct iov_iter to;
+
+	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
+
+	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
+		 fid->fid, offset, count);
+
+	err = 0;
+	clnt = fid->clnt;
+
+	rsize = fid->iounit;
+	if (!rsize || rsize > clnt->msize - P9_READDIRHDRSZ)
+		rsize = clnt->msize - P9_READDIRHDRSZ;
+
+	if (count < rsize)
+		rsize = count;
+
+	/* Don't bother zerocopy for small IO (< 1024) */
+	if (clnt->trans_mod->zc_request && rsize > 1024) {
+		/* response header len is 11
+		 * PDU Header(7) + IO Size (4)
+		 */
+		req = p9_client_zc_rpc(clnt, P9_TREADDIR, &to, NULL, rsize, 0,
+				       11, "dqd", fid->fid, offset, rsize);
+	} else {
+		non_zc = 1;
+		req = p9_client_rpc(clnt, P9_TREADDIR, "dqd", fid->fid,
+				    offset, rsize);
+	}
+	if (IS_ERR(req)) {
+		err = PTR_ERR(req);
+		goto error;
+	}
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "D", &count, &dataptr);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto free_and_error;
+	}
+	if (rsize < count) {
+		pr_err("bogus RREADDIR count (%d > %d)\n", count, rsize);
+		count = rsize;
+	}
+
+	p9_debug(P9_DEBUG_9P, "<<< RREADDIR count %d\n", count);
+
+	if (non_zc)
+		memmove(data, dataptr, count);
+
+	p9_req_put(clnt, req);
+	return count;
+
+free_and_error:
+	p9_req_put(clnt, req);
+error:
+	return err;
+}
+EXPORT_SYMBOL(p9_client_readdir);
+
+int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
+			 dev_t rdev, kgid_t gid, struct p9_qid *qid)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	err = 0;
+	clnt = fid->clnt;
+	p9_debug(P9_DEBUG_9P,
+		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
+		 fid->fid, name, mode, MAJOR(rdev), MINOR(rdev));
+	req = p9_client_rpc(clnt, P9_TMKNOD, "dsdddg", fid->fid, name, mode,
+			    MAJOR(rdev), MINOR(rdev), gid);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P, "<<< RMKNOD qid %x.%llx.%x\n",
+		 qid->type, qid->path, qid->version);
+
+error:
+	p9_req_put(clnt, req);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_mknod_dotl);
+
+int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
+			 kgid_t gid, struct p9_qid *qid)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	err = 0;
+	clnt = fid->clnt;
+	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
+		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
+	req = p9_client_rpc(clnt, P9_TMKDIR, "dsdg",
+			    fid->fid, name, mode, gid);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "Q", qid);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P, "<<< RMKDIR qid %x.%llx.%x\n", qid->type,
+		 qid->path, qid->version);
+
+error:
+	p9_req_put(clnt, req);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_mkdir_dotl);
+
+int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	err = 0;
+	clnt = fid->clnt;
+	p9_debug(P9_DEBUG_9P,
+		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
+		 fid->fid, flock->type, flock->flags, flock->start,
+		 flock->length, flock->proc_id, flock->client_id);
+
+	req = p9_client_rpc(clnt, P9_TLOCK, "dbdqqds", fid->fid, flock->type,
+			    flock->flags, flock->start, flock->length,
+			    flock->proc_id, flock->client_id);
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "b", status);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P, "<<< RLOCK status %i\n", *status);
+error:
+	p9_req_put(clnt, req);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_lock_dotl);
+
+int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	err = 0;
+	clnt = fid->clnt;
+	p9_debug(P9_DEBUG_9P,
+		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
+		 fid->fid, glock->type, glock->start, glock->length,
+		 glock->proc_id, glock->client_id);
+
+	req = p9_client_rpc(clnt, P9_TGETLOCK, "dbqqds", fid->fid,
+			    glock->type, glock->start, glock->length,
+			    glock->proc_id, glock->client_id);
+
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "bqqds", &glock->type,
+			  &glock->start, &glock->length, &glock->proc_id,
+			  &glock->client_id);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P,
+		 "<<< RGETLOCK type %i start %lld length %lld proc_id %d client_id %s\n",
+		 glock->type, glock->start, glock->length,
+		 glock->proc_id, glock->client_id);
+error:
+	p9_req_put(clnt, req);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_getlock_dotl);
+
+int p9_client_readlink(struct p9_fid *fid, char **target)
+{
+	int err;
+	struct p9_client *clnt;
+	struct p9_req_t *req;
+
+	err = 0;
+	clnt = fid->clnt;
+	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
+
+	req = p9_client_rpc(clnt, P9_TREADLINK, "d", fid->fid);
+	if (IS_ERR(req))
+		return PTR_ERR(req);
+
+	err = p9pdu_readf(&req->rc, clnt->proto_version, "s", target);
+	if (err) {
+		trace_9p_protocol_dump(clnt, &req->rc);
+		goto error;
+	}
+	p9_debug(P9_DEBUG_9P, "<<< RREADLINK target %s\n", *target);
+error:
+	p9_req_put(clnt, req);
+	return err;
+}
+EXPORT_SYMBOL(p9_client_readlink);
+
+int __init p9_client_init(void)
+{
+	p9_req_cache = KMEM_CACHE(p9_req_t, SLAB_TYPESAFE_BY_RCU);
+	return p9_req_cache ? 0 : -ENOMEM;
+}
+
+void __exit p9_client_exit(void)
+{
+	kmem_cache_destroy(p9_req_cache);
+}